A few thousand years ago, let's not get too caught up in dates, but less than ten thousand years ago, the ice age came to an end. The ice age had been so severe in Britain that it had killed off the tree life. Slowly the tree population of Britain started to re-form as it became possible for trees to survive. This tree life came from the south where trees had survived. However coinciding with this re-population of plant life in Britain was the thawing of the glaciers.

The glaciers were the large mountains and rivers of ice which existed in Britain and in Europe at that time, caused by the freeze; they still exist in Antarctica. The water from these ran down and caused the sea level to rise and form what we now call the English Channel. Yes, Britain used to be connected to Europe by land; the English Channel is not deep, hence it is possible to dig a tunnel under it. By the time the thaw was completed and continental Europe was cut off from Britain, only 33 species had re-entered. We refer to these as native British trees.